What are the roles to form the bolt row groups for the EC3 verifications for the bolted connections?

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Note: this option is available starting with the 2012 version of Advance Design

When a bolted joint is verified according to the Eurocode 3 standard, the Equivalent T-stub method is used, and according to this method the bolts must be verified as individual rows and as bolt row groups.

To exemplify this we will use a Flange haunch joint similar to the one displayed in the figure. The joint will be affected by a positive moment like in the following figure.

The moment orientation will impose the position of the connection rotation center and the bolt row numbering. The bolt row numbering will start with the most solicited one, this being the bolt row farthest to the connection rotation center.

According to Eurocode 3, EN 1993-1-8-2003, chapter 6.2.6.4.2 (3), the bolt row groups, either side of the stiffener, should be modeled as separate T-stub flanges. The design resistance and failure mode should be determined separately for each equivalent T-stub.

The bolt row groups will be formed and verified for the beam end plate and for the column flange.

The beam end plate bolt row groups can be different from the column flange bolt row groups, this depending of the presence and positions of the stiffeners inside the connection. The beam bottom flange will be considered a stiffener for the beam-haunch assembly; therefor there will be no bolt row group that will contain bolt rows both sides of it.

The Advance Design Steel Connection report will contain only the bolt row groups that are verified for both or at least one of the two elements: the beam end plate and column flange.

The bolt row groups included in the Advance Design Steel Connection report for a connection similar to the one presented, and the corresponding verification are represented in the following table:

The bolt row groups that cannot be generated for any of the two elements will not be generated or displayed in the report.

The verifications for the first two bolt row groups, 1-2 and 2-3, are shown as they are presented in the Advance Design Steel Connection report: